Gear-testing machine



Sept. 22, 1.925

c,- G; OLSON "TESTING MACHINE Filed new, 10 19.19-

3 Sheets-Sheet I Lmk NS d I Q l, KM l 1 1,554,646 FFIcE.

CARL G. @IiSDN, OF CHICAGO, ILLINOIS, ASSIGNOR T0 ILLINOIS TOOL WORKS, OF

CHICAGO, ILLINOIS, A CORPORATIUN 01E" ILLINOIS.

GEAR-TESTING E.

' Application filed November 10, 1919. fierial No. 336,928.

To all whom it may concern: v

Be itknown that I, CARL G. ULSON, a citizen of the United States, residing at (1hr cago, in the county of Cook and State of Illinois, have invented a certain new andnseful Improvement in Gear-Testing Machines, of which the following is a speclfication.

My invention relates to gear testing ma-v chines especially for the testing of the teeth of involute gears- One object of the invention is to provide means for testing the accuracy of configuration of the gear teeth. A patent showing a machine for an analogous purpose was granted to me May 275 1919, No. 1,304,592. Another ob ect of rny invention is to provide means for. readily determining the pressure angle of the teeth, I obtain my objects by the mechanism llustrated in the accompanying drawings, in which Figure 1 is a top plan view of thecomplete machine.

Figure 2 is a .longitudlnal sectional elevation on Jthe line 22, Figure l.

Figure dis a sectional elevation line 33, Figure 2. a 1

Figure 4 is asectional elevation on the line H, Figure 1.

Figure 5 is a sectional .ze levation on the line 5+5, Figure l. Figure, 6 is a perspective component parts of the protractor and contact arm.

Figure 7 is a sectional-view taken crosswise of the testing carriage.

Figure 8 is a verticalisectional detail view taken crosswise of the contact arm of the protractor;

Like numerals denote like parts 'thruout the several views.

In the form selectedto illustrate the invention the "machine has a main frame 1 having a pair of longitudinal guides 2,".2.

t one point said guides support a socket member 3 which is rigidly held in proper on the position on the guides bylmeans of a set" screw 1- as shown in Figure 5. The socket member receives I and supports the lower conical end of a stationary upright arbor .6. Fitting'over said arbor is a sleeve "7 having an annular flange" 8 atits lower end. This sleeve rests upon the socket member and is freely rotatable upon the arbor. as an axis. Encircling the sleeve and resting upon the flange 8 is a disc or roller 10 having a diameter equal tothe itch diameter of the gear 11, to be teste A. spacing collar 12 surrounds sleeve 7 between disc 10 and the gear 11- A spacing collar 13 surrounds sleeve 7 above the gear 11. A knurled-nut 14 screws upon the upper threaded end of sleeve 7 and when this is screwed downtight against the collar 13" it clamps the gear and the disc together so as to make them rotate as a unit.-

Slidably mounted upon the guides. 2 at one side of the socket member 3 is a carriagef 17. For identification this may be termed the contact carriage as it keeps the straight edge or track in contact with-the pitch circle disc as will be presently under stood. This is longitudinally bored to slidingly receive and guide an internally threaded sleeve 18 which extends parallel to in a stationary bearing 21 which forms a pa1*t ht';the main frame. A hand wheel 22 is fastened to said screw in position to abut the outer end of bearing 21. A collar 23 is rigidly fastened to the screw in position to guides 2. An adjusting screw 20 screws "into said sleeve. Said screw is journaled abut the inner end of said hearing. The result is that by rotating the hand wheel in one direction or the other the sleeve 18 Y may be moved longitudinally of the machine view of the and toward 'and from disc 10. The carriage 17 isslidable relatively to sleeve 18 and the carriage is constantly urged toward disc 10 by means of a helical compression spring 25 which encircles a stud 26, screwing into or otherwise rigidly fastened. to the carriage. At one end the spring abuts the carriage and at the other end fits into and abuts the bottom of a socket 28 formed-in an upstanding post 29 rising from the sleeve 18.- The outer end of the stud 26 is threaded to take the nut 30 which abuts the outer end of post 29. By screwing this nut one way or the other the tension of spring 25 may be regulated. This nut consequently aiiordsmeans for varying the pressureof the sleeve 18 against the carriage and in turnthe pressure 'of the carriage toward the disol L l The said carriage 17, which travels longi-' tudinally of the machine, has crossguides 33 which support a cross-carriage 34. For identification this may be called the operating carriage, as it is the one which the bperator causes to travel back and forth in making the test. Said carriage has a straight edge or track 35 fastened to one side to make rolling contactwith the disc 10. The carriage also has a nut 36 which takes an operat ng screw 37 journaled in a bearing 38 formed at the front of the lon itudinally moving carriage 17, as shown in etail at the right end of Figure 3. TlllS operating screw "is rotated by means of a hand wheel 40 having a hub 41 which abuts the outer end of the bearing 38-- A collar- 42 is fastened to the screw in p'ositionto abut the inner end of thegbearing. Thus by rotating the operating handj wheel 40 one way or the other the operating carriage 34 may belmoved forward or backward across themain frime.

Carriage 34 is provided with guides 45 arranged parallel. to the operating screw 37.

These guides support the indicatorcarriage I This movement is for bringing the indicator pointer to zero position when the contact arm is in contact with the as will be explained.

The indicator carriage 46 carries an indicator 54 at its rear end. .The indicator is provided with a dial 55 and pointer 56.

The pointer is operated by means of a plunger 57 which is longitudinally movable in a line'parallel to the axis of screw 48. The indicator 54 is what is commonl known as a multiplying dial indicator an article which is known commercially. It is sufficient for the present purpose to say that the plunger 57 is cared. to the pointer in such manner that Winn the plunger is pushed inward against t 1'. force of an internal cushion spring the' p inter will rotate, thus indi- ,cating in an exag erated degree the amount of movement of t e plunger.

. Mounted upon; the indicator carriage is a testing carriage 60. This is mounted upon the indicator carriage 46 in such manner as to travel thereon in the direction of the length of the plunger 57. It has a contact finger 61 at its rear end which engages the end of the plunger 57 The testing carriage moves very freely, the frictional resistance being reduced to a minimum by balls 62 sliding in grooves in the indicator and testing carria es.

Fastene to the testing carriage is a protractor having a base plate 65 shown in pergearto be tested,

held assembled by a screw 69. Plate 65-.

is secured to the testing carriage 60 means of a' clip held by a screw 71 1n pmition to engage the arm 72 which forms an. extension of said base plate.

Plate 68s.

is not a complete disc but is segmented to produce a flat side 73 at the back; A con tact arm 75 bears against the side 73 and the parts are held assembled by a tie bar 76.T-'

This is held tov plate 68 by a screw 69 and to the contact arm 75 by a screw. 7 7, as'shown in perspective in igure 6. Arm 75 has a longitudinal slot 0 which receives a rib 81formed at the bottom of the rear end of bar 76. This permits the arm 75 to be adjusted longitudinally with reference-to the upper protractor plate 68. .These parts are shown in detail in Fig. 8. In order to brace the arm 75 and hold-it down uponthe extension 72-of plate 65 it is desirable to form a keeper arm 83 integral with arm 72, said keeper arm overlying the contact arm as best shown in Figure 1. i

From the foregoing it will be-seen that whenthe parts are thus assembled the contact arm 7 5' is rotatable in unison with protractor plate 68 about the axis of screw 69 and that the protractor parts and contact arm 75are very freely movable as a unit towards and from "the. plunger 57 of the indicator 54. I 1

The parts above described are the only' ones concernedwith my present invention."

As built commerciallyhowever it isdesirabieto provide, in the same machine, means for otherwise testing the gear 11. For this purpose a correct gear for testing pure,

poses'is held in mesh with gear 11. A screw having a hand wheel 96 is journaled' in a fixed bearing 97 in the machine frame and held against longitudinal movement by a collar 98 co-operating with the hub of said hand wheel. Said screw works in a nut 100 mounted on a test carriage 102 upon which is rigidlv mounted a thrustindicator 103. This indicator has a spring backed plunger 104 which actuat'es the pointer 105 of the indicator. This plunger is engaged by arod 110 rigidly fastened to a'gear car- Tier 106, which is slidable on carriage 102.

Said carrier has an upright arbor 108 on which gear 90 is rotatably mounted. Rod 110 slides in carriage 1'02 and a compression spring 111 is interposed between the carriage and gear carrier 106. When the gears 11 and 90 are rotated while in'mesh, if the teeth of the gear 11 are out of true they will permit the testing gear 90 to approach more nearly to the center of gear 11, or-will force gear 90 further awav from the center WP so that the two rotate as a single piece about the arbor 6. Next, the hand wheel 22 is manipulated in such manner as to bring the track into contact with the disc 10. The pressure of the track against the disc will be a yielding one on account of the presence of the springs 25. Another preliminary' is to angularly position the upper v protractor plate 68.and with itthe contact arm 7 5. Frequently, when gears are sent in to be tested, their pressure angle is not known. In such case the operator estimates or guesses at the angle and adjusts the up.-

\ per protractor plate and contact arm accordingly. Fourteen and a half degrees is a common angle and the operator would probably try this first. The operator then brings the contact arm 75 into contact with the side of a gear tooth, as shown in Figure 1, and while keeping it there manipulates the screw 48 in such manner as to bring the indicator pointer to zero position. The indicator plunger, backed up by the spring .within the indicator, pushes against the finget 61 on the testing carriage and this keeps the contact arm in contact with the gear tooth under substantially uniform pressure. The machine is now set ready to make the test. The actual-test is made by slowly ro-' 'tating the hand wheel 40 back and forth and observing the position of the pointer.

This movement of the operating carriage 34 and track 35 causes the disc 10 torotate and to produce a corresponding rotation of the gear wheel 11. Now, according to the properties of involute gears, if the contact arm 75 has been set at the proper pressure angle and the gear teeth are accurately configurated, the engaged gear tooth will cause the contact arm to travel at the same rate as the track 35. As the indicator carriage 46 is fixed relatively to the operating carriage 34, there should be no relativemoveinent between the latte-rand the testing carriage 60. In such case, the pointer will remain at zero. But if the pointer does move, that there issuch relative move showin ment t on the operator knows either that the contact arm is not set at the correct pressure angle or that the gear tooth is imperfect, or both. By testing several teeth he will soon be able to determine whether the movement of the indicator; pointer results. from improper setting of theco'ntact arm or improper configuration of the tooth."

By the cut and try method, he will soon be 'able to determine what the pressure angle is and when this has once been determined and the arm has been. set correctly at'that angle each individual tooth may be tested in thesame manner and the inaccuracies,

"design there shown, the contact arm or contactor has a ball shaped head which makes point contact, so to speak, with the gear tooth. Such a construction iscapable of showing the aberration, but does not ailord direct means for determining the pressure angle of the tooth. In the form shown in the present case, the contactor 7 5 has a straight edge ficr contacting the side of the tooth.- It is therefore analogous to the acting half of a rack tooth. Rack teeth for involute gears are, of course, straight sided, and the angle of inclination of the side of the rack tooth constitutes the pressure angle. The acting side of the contactor in my present case therefore forms an analogue of the acting side of a rack tooth and hence by changing the angle of the contactor until a perfect gear toothwillc'ause no movement of the indicator pointer, the pressure angle of thetooth may be found,

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is: a

means for causing the gear to'be tested, to

rotate in unison withthe roller, a contartor, means Whereby'the contaotoris supported by the track for angular and longitudinal bodily movement relative to the track, andmeans for detecting relative movement between the contactor and the track, the con tactor havm astraight edge for engaging the side of tie tooth to be tested, whereby if the contactor be not set at't-he truepressure angle a relaive movement between the contactor and the track will occur, even tho the tooth be accurately configurated, thus enabling the operator to determine the pressure angle of the gear teeth.

2. A gear tester having a track, a roller adapted to rotate in contact with said track, means for causing the gear to be tested torotate in unison with the roller, a contactor having a straight edge for engaging the side of the tooth to be tested, connections between the contactor and the track adaptedto permit relative'movement between them, means for indicating such relative movement, and means for enabling the angle of the contactor relative to the track to'be varied. 1

3. A. gear testerhaving. a support .for the gear to be tested, a contactor provided with a straight edge for engaging the side of a 'tooth. of a gear on said su'pport,a

carriage for supporting said cont actor, said Jcontactor being angularly a ustable rela tively to the carriage, a support for said sald CZII'IlfigHPIOVlClBCl with a track, a roller on the gearfsupportadapted to cooperate with said track, means for securing the roller to the gear to be tested whereby the two will rotate in unison, and meansfpr indi- 'cating', relative movement between-the contactor and the track.

4:, A: geartester havinga ingtwo, relatively rotatable parts, a" contactor rotating in unison with one of the protractor parts, a carriage for supporting the other protractor part, a. support for said carriage, said supporthaving atrack,

' movable in unison with it, a roller onthe -tate in unison, said means being adapted; to hold sald gear in engagement with the gear support adapted tocooperate with said track, and means for securing the gear too be tested to the roller whereby the two rocontactor, I 4

5. A gear tes'ter having a support for the gear to be tested, a 'protractor including two relatively rotatableparts, a contactor rotating in unison with one. of the protractor parts, a carriage for supporting the other protractorjpart, said protractor having-a straight edge adapted to engage the side of a tooth of a gear on said support, a

support for saiicarriagehaving atrack movable 1n IlIllSOIlsWllZll 1t, a roller on the gear support adapted to rotatein contact,

with said track, clamping-means for'caus' .ing the gear to rotate in unison with. the

roller, and means for indicating the rela tive movement between the contactor and the track lengthwise of the track.

A gear tester having a support for the gear to be tested, a contactor provided with a straight edge for-engaging the si de of a tooth of a gear on said support a carriage forsupportingsaid cbntaetor, said .eontac tor being angularly adjustable relatively to the carriage, asupport for said carriage pro-- VlClGd with a track, a roller entire gear support adapted 'to cooperate with said track, means for securing the roller to the gear toibe tested whereby the two will rotate in unison, an'indicator secured to, sa'id support, said indicator having a polnter and aplunger whereby it is actuated, said' plunger being adapted to engage said car riage and urge it i) a direction tending to hold the contactor in engagement with the tooth to be tested.

7. A gear tester having a support for the.

gear to be'te'sted, a contactor provided with a straight edge for engagingthe side of sup-port for. the gear to be tested, a protractor includa tooth of a gear on said'support, a carriage for supporting said contactor, sald 'contactor being angularly adjustable relatively to the carriage, a support for said.

carriage provided with a track, a roller on the gear support adapted to cooperate with said track, means for securing the roller to the gear to be testedwhereby the two will rotate in unison, means for indicating relative movement between the contactor -and the track, and means for pressing the track and roller towards each other.

' 8. A gear tester ha vinga roller and means for fastening to it thgearto be tested, a

support fgr the gearand roller, a track adapted to cooperate with the roller, an

operating carriagewhereto, the track issecured,. a support for said carriage, a screw adapted to-move'the carriage in the directionof the length of the track,- anindicator movable in unison with the carriage,

a contaetbr having a straight edge'for engaging the side of a tooth of a gear on the.- gear support, and a testing carriage.

whereto the indicator is fastened, said'testingcarriage being adapted to actuate the indicator, andbein g supported on the operatingcarriage and movablev relatively to the indicator in the direction of the length of the track.

9. A gear tester having aroller and means .for fastening to it the gear tobe tested, a support for the gearliand roller, a track adapted to cooperate with the roller, an

operating carriage whereto the track is setrack and roller toward each other.

10. A gear tester having a roller adapted to rotate in unison with the gear to be tested,

a support for the gear and roller, a track adapted to cooperate witlfthe roller, an operating carriage for producing relative movement between the roller and the track, an indicator carriage mounted on the operating carriage, an indicator-secured to the indicator carriage, a. testing carriage mounted on the indicator carriage, and a 'contactor secured to the testing carriage, the testing carriage being adapted to .op-

erate the indicator andthe indicator carriage being adjustable relatively to the operating carriage whereby the indicator'may be brought to zero position when the conrolling contact with a tooth of the gear on said supporting means, means for moving the other carriage and rotating the gearin predetermined ratio, having regard to the linear velocity of the gear at the pitch circle, and means for indicating any rela: tive movement of the carriages.

12. A machine. for testing gears having involute teeth, said machine having means for rotatably sulpporting the gear to be tested, two carriages movable parallel to each other and parallel to a plane tangential to the pitch cylinder of the gear on said support, a straight edge contactor on one of said carriages, means for yieldingly-holding; said contractor in engagement with a tooth of said gear, means -for rotating the gear and moving the other carriage tangentially to it in predetermined ratio, and means for indicating any relative movement of the carriages. T a 13. A machine for testin gears having involute teeth, said machine having means for rotatably supporting the gear to be tested, a straight edge contactor for rolling upon a tooth of agear on said supporting means, two carriages movable parallel to each other and parallel to the pitch cylinder of the gearto be tested, the first-carriage supporting the contactor, and the second carnage supporting the first carriage, means for moving the second carriage-and rotating the gear so that the'sp'eed of the second,

carriage is the same as the linear speed of carriages.

the pitch circle of the gear, and'means for indicating any relatlve movement of said 14. Av machine for testing gears having involute'teet-h, said machine having means 'for rotatably supporting the gears to be tested, a straight edge contactor for rollingupon a tooth of the gear upon said support-' ing means a carriage on which said contact-or is mounted, said carriage being movable parallel to a plane tangential. to the pitch cylinder of the gear, a second carriage movable parallel to the first one for-support ing it, means for moving the second carriage and rotating the gear so that the speed of the second carriage is the same as the linear speed of the pitch circle ofthe gear, means for indicating any relative movement of said carriages, a third carriage movable at right angles to the others for supporting them,

and means for yieldingly urging the third carriage toward the ear to thereby main- I taln pressure contact etween the contactor and-the gear'tooth. 1

,l5. A machine for testing gears having i moved by the gear tooth, means for rotating the gear while the tooth is incontact with the contactor, and means for indicating whether or not the contactor has been moved linearly an amount equal to the areaate movement of the gear at the pitch line.

16. A machine for testing gearsha'ving involute teeth, said machine having means for rotatively supporting the gear to be tested, a straight edge contactor for engaging a tooth of the gear upon the gear supporting means at different points alongthe 1 toothicurve, a support for said contactor movableparallel to a plane tangential to the pitch cylinder of the gear upon said gear supporting means, a carriage on which said support is mounted, said carriage being movable in the same directionas said support, means for,rotating"the gear a definite amount,'and means-for moving the carriage an amount corresponding to the angular movement of the gear and .'means tor-indicating the relative 'movement, if any, between the carriage and the-support .to there by indicate the departure, if any, of the 1tooth form from the form that it should lave.

17. A machine for testing gears having involute teeth, said machine having means i for r'otatably supporting the gears to ,be

tested, a straightedge contactor for rolling upon .a tooth of the gear upon the gear supporting means, a carriage .on which said contactor is mounted, said carriage being movable parallel toa plane tangential to the .pitch cylinder of'the gear, a second carriage movable parallel to the first one for supporting it, means for moving the second speed-of the-second carriage is the same as the linear speed of the pitch circle of the gear, means for indicating any relative movement of said carriages, a third carriage movable *atright angles to the others for supporting them, means for yieldingly urging the third carriage toward the gear to 1 scnibed my name.

4 CARL G. OLSON.

.115 carriage and'rotating the gear so that the 

